title: Neural network assessment of perioperative cardiac risk in vascular surgery patients.
abstract: Neural networks were developed to predict perioperative cardiac complications with data from 567 vascular surgery patients. Neural network scores were based on cardiac risk factors and dipyridamole thallium results. These scores were converted into likelihood ratios that predicted cardiac risk. The prognostic accuracy of the neural networks was similar to that of logistic regression models (ROC areas 76.0% vs 75.8%), but their calibration was better. Logistic regression overestimated event rates in a group of high-risk patients (predicted event rate, 64%; observed rate 30%; n=50, p<0.001). On a validation set of 514 patients, the neural networks still had ROC similar areas to those of logistic regression (68.3% vs 67.5%), but logistic regression again overestimated event rates for a group of high-risk patients. The calibration difference was reflected in the Hosmer-Lemeshow chi-square statistic (18.6 for the neural networks, 45.0 for logistic regression). The neural networks successfully estimated perioperative cardiac risk with better calibration than comparable logistic regression models.
authors.affiliation: Department of Internal Medicine, University of Southern California School of Medicine, Los Angeles, USA. PablovLapuerta@ccMail.bms.com
authors.forename: P
authors.initials: P
authors.lastname: Lapuerta
authors.forename: G J
authors.initials: GJ
authors.lastname: L'Italien
authors.forename: S
authors.initials: S
authors.lastname: Paul
authors.forename: R C
authors.initials: RC
authors.lastname: Hendel
authors.forename: J A
authors.initials: JA
authors.lastname: Leppo
authors.forename: L A
authors.initials: LA
authors.lastname: Fleisher
authors.forename: M C
authors.initials: MC
authors.lastname: Cohen
authors.forename: K A
authors.initials: KA
authors.lastname: Eagle
authors.forename: R P
authors.initials: RP
authors.lastname: Giugliano
mesh_terms: D001499:Bayes Theorem; D002138:Calibration; D006331:Heart Diseases / Q000000981:diagnostic imaging / Q000517:prevention & control*; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008404:Massachusetts; D016571:Neural Networks, Computer; D011183:Postoperative Complications / Q000517:prevention & control*; D012372:ROC Curve; D011877:Radionuclide Imaging; D018570:Risk Assessment; D012307:Risk Factors; D013794:Thallium Radioisotopes; D014656:Vascular Surgical Procedures
chemical_list: D013794:Thallium Radioisotopes